The present invention relates to a method comprising a multistep process recovering betaine, erythritol, inositol, sucrose, mannitol, glycerol and amino acids from corresponding starting materials by using a weakly acid cation exchange resin in a column. More particularly, the present invention relates to the use of a weakly acid cation exchange resin in a chromatographic column in a method for multistep process for recovering products from solutions obtained from the processing of beet derived solutions, such as beet molasses, betaine molasses and vinasse. The corresponding starting materials are especially beet molasses, betaine molasses, cane molasses, syrups, thick juices, raw juices, corn steep and cane based solutions.
Chromatographic separation has been used for recovering betaine, inositol and sucrose from natural materials such as beet molasses, betaine molasses and vinasse. The resins most commonly used in the known chromatographic separations have been strongly acid cation exchangers, i.e. sulfonated polystyrene cross-linked from 3.5 to 8% by weight with divinyl benzene, the resin being in monovalent or divalent form. However, the separation of inositol by using strongly acid cation exchange resins has turned out to be difficult. There is no experience of separating erythritol and mannitol from beet derived solutions. Water is generally a preferred eluant, but the problem when using water is that the various products, such as betaine, erythritol, inositol, sucrose, mannitol, amino acids and mixtures of amino acids have similar retention times, whereby the fractions will overlap.
Publication WO 94/17213 describes a process for fractioning molasses using a chromatographic simulated moving bed system. The product or the products are collected during a multistep sequence comprising the steps of feeding molasses, elution and recycling. Fractionation of molasses denotes fractionation of various vegetable derived by-products of the food and fermenting industries, such as beet and cane molasses, stillage, vinasse, slop, wood molasses, corn steep liquor, wheat, barley and corn molasses (hydrolyzed C-starch). Strongly acid cation exchange resin were preferably used as the chromatographic column packing material, the resins used in the examples had a polystyrene/divinylbenzene backbone and were activated with sulphonic acid groups. The resin was preferably in monovalent form such as sodium or potassium or as a mixture of these forms. The products of the process comprised residue and sucrose and/or betaine.
WO 98/53089 describes a process for the simultaneous obtaining of converted and non-converted sugar and/or non-sugar products, especially isomaltulose and/or trehalulose and betaine or invert sugar from plant derived solutions. The sucrose containing solution is subjected to transglucosylation and in the next phase recovering from said transglucosylated solution isomaltulose and/or trehalulose and non-converted sugar and/or non-sugar products by a process including separate chromatographic recovery. A strong acid cation exchange resin cross-linked with DVB in Na+ form was used.
DE 2 232 093 discloses a process for separating sugars from molasses by using ion-exclusion resins. Eluant used in the process is water and sugar containing solution. The eluant is recycled back to the process. Low purity fractions are also used for reviving the resin. Strong acid cation exchange resin is mentioned in the examples.
Japanese patent publication No. 39-5429 describes a process for separating betaine from sugar containing liquid especially sugar beet derived, by ion exchange resin. In the process betaine is separated by using strong acid cation exchange resin in Na+ form by eluting it with water without any regenerants.
DE 2 362 211 describes a method for separating sugars from molasses by liquid chromatography. A cation exchanger in Ca2+ form is used in the method. Erythritol, inositol and mannitol have not been mentioned in the patent, neither does it suggest fractioning of betaine. In the examples a strong acid cation exchange resin is used.
U.S. Pat. No. 4,359,430 discloses a process for recovering betaine from molasses by using a chromatographic column of a salt of a polystyrene sulphonate cation exchange resin cross coupled with DVB, and eluting with water. The first fraction separated is a waste fraction and the second fraction contains a substantial proportion of the sugars of the feed solution, the third fraction consists principally of betaine.
Munir, M., (Zucker 28 (1975) No. 6 pp. 286-294) has described a desugarization of molasses by means of liquid distribution chromatography. In the article betaine is mentioned but not sugar alditols, and even though the betaine is mentioned it has not been suggested that betaine should be recovered. The strong acid cation exchange resin is used in Ca2+ form.
From U.S. Pat. No. 5,127,957 is known a method wherein betaine is separated from beet molasses using a chromatographic simulated moving bed system having at least three chromatographic columns connected in series. Strong acid cation exchange resins were used where the resin contained sulphonic acid groups. The resin was regenerated into sodium form.
U.S. Pat. No. 4,358,322 discloses a process for separating fructose from a feed mixture comprising fructose and glucose. The process comprises contacting the mixtures with an adsorbent comprising aluminosilicate or zeolite. The adsorbent contains one or more selected cations at exchangeable cations sites. The cations are selected from the group consisting of sodium, barium and strontium. The cationic pairs used in the cationic sites are selected from the groups consisting of barium and potassium and barium and strontium.
From U.S. Pat. No. 4,405,377 is known a process for the separation of a monosaccharide from at least one other monosaccharide. The aqueous feed solution of the monosaccharides is diluted with ethanol and contacted with an adsorbent comprising a crystalline aluminosilicate. The crystalline aluminosilicate is selected from X zeolites and Y zeolites.
From U.S. Pat. No. 4,333,770 is known that various sugars and particularly sucrose may be separated from mixtures of sugars including glucose, fructose, raffinose etc. by treating an aqueous solution of the molasses with an adsorbent which will selectively adsorb sucrose thereon. The adsorbent comprises a shaped replication of inorganic support particle aggregates. The adsorbent consists of a carbonaceous pyropolymer containing at least carbon and hydrogen atoms. Alcohol solutions are used as eluents. The preferred alcohols contain methanol and ethanol.
From U.S. Pat. No. 4,405,378 is known a process for separating sucrose from aqueous solutions containing sucrose and betaine and mineral salts. The feed solution is contacted with an adsorbent which comprises activated carbon powder bound with a binder material. The binder material consists essentially of a water permeable organic polymer selected from the group consisting of cellulose nitrate, a cellulose ester and a mixture of a cellulose nitrate and cellulose ester. The sucrose is removed from the adsorbent by treatment with a desorbent material comprising a water and methanol mixture. It has not been possible to separate betaine from the mineral salts, only the separation of sucrose is possible.
Kouji Sayama et al. (Proc. Res. Soc. Japan Sugar Refineries Technol. 1980, vol 29, 1-27) describe recovery of sucrose from molasses using a strongly acid cation exchange resin in sodium form. They also describe separation of betaine and recovery of inositol from molasses by using a strongly acid cation exchange resin in Ca2+ form.
McCready, R. M. et al (1965) describe the preparation of galactinol and myoinositol from sugar beet syrup by chromatography on a cation exchange resin. A strongly acid cation exchange resin in potassium form was used for separation of myoinositol and galactinol. Water was used as eluant.
It has surprisingly been found that when using in a multistep process a weakly acid cation exchange resin, products can be recovered from solutions obtained from the processing of e.g. beet molasses, betaine molasses and vinasse. The order of elution of valuable carbohydrates in the chromatographic column is different from that previously known. An additional feature is that the elution order of components with the weakly acid cation exchange resin seems to be affected strongly by the hydrophobic/hydrophilic interaction of the component of the product with the resin and this can be used advantageously in the multistep process. In the chromatographic column other features are preferably e.g. ion exclusion and size exclusion. Other process steps used in the multistep process are e.g. crystallization, evaporation, ion exchange and filtration. It seems that if the resin is in hydrophilic form, the most hydrophobic monosaccharide is eluted first and the most hydrophilic last. This results in a clearly different order of separation than when used a strongly acid cation exchange. This is especially advantageous when fractioning a multicomponent solutions.
The above mentioned objects and others are accomplished by the present invention, which relates to a multistep process for recovering one or more products from a solution containing betaine, erythritol, inositol, sucrose, mannitol, glycerol, amino acids and mixtures thereof by using chromatographic separation comprising at least one step, where a weakly acid cation exchange resin is used in at least one chromatographic column for the chromatographic separation.